The present invention generally relates to a lighting device. More particularly, the present invention relates to a portable battery-powered lighting device.
Portable lighting devices, such as flashlights and lanterns, are known which produce a directional beam of light. FIG. 1 shows the construction of a relatively low-cost flashlight 10 currently marketed by the assignee of the present invention. Conventional flashlight 10 includes a battery housing 12 of a molded plastic construction, which further serves as a handle for holding the flashlight. As shown in FIG. 1, battery housing 12 has a generally cylindrical shape with one end having an integrally-molded end wall 13. The open end of battery housing 12, in which batteries may be inserted or removed, includes external threads 14 for engaging the internal threads 16 of a shroud 18. Battery housing 12 further includes a slot 20 formed in a side thereof in order to enable a raised portion 22 of a sliding electrical contact 24 to be secured to a switch 26 provided on the exterior of battery housing 12.
Flashlight 10 further includes a spring 28 that is inserted within the battery compartment defined by battery housing 12. Spring 28 is provided in contact with the end wall 13 to bias the inserted batteries forward into contact with a positive terminal 30 of a light bulb 32. Spring 28 further provides an electrical contact to the negative terminal of the rearmost battery inserted into battery housing 12. A fixed electrical contact 34 is also provided within the battery compartment of battery housing 12 to provide an electrical connection between spring 28 and a moving electrical contact 24.
Flashlight 10 further includes a bulb holder 36 having internal threads 38 for engaging external threads provided as a negative electrical contact 40 of light bulb 32. Bulb holder 36 also includes either external threads 42 or a welding surface for securing bulb holder 36 within an aperture 44 provided in an electrical contact shell 46. With such an arrangement, the negative contact terminal 40 of light bulb 32 is electrically coupled through holder 36 to contact shell 46. At the same time, with light bulb 32 screwed into bulb holder 36, positive terminal 30 extends beyond the rearward opening of holder 36 so as to come into contact with a positive terminal of the forwardmost inserted battery. To turn light bulb 32 on and off, switch 26 is slid axially along battery housing 12 thereby moving sliding contact 24 forward and rearward into and out of contact with contact shell 46.
Flashlight 10 additionally includes a reflector 48 having a central aperture for receiving light bulb 32 such that light emitted from light bulb 32 is reflected in a generally forward direction. A lens 50 is provided across the forward opening of the flashlight as defined by shroud 18 and reflector 48 to protect the light bulb from damage. The lens 50, reflector 48, contact shell 46, light bulb 32, and bulb holder 36, which together form a head structure of flashlight 10, are secured across the open end of battery housing 12 by shroud 18, which includes a lip at its forward end to prevent lens 50 and the components positioned to its rear from falling out of the forward end of shroud 18.
Although flashlight 10 represents a relatively low-cost flashlight, it nevertheless includes no less than eleven components. Further, due to the number of potential component interfaces through which water could penetrate to reach the interior of battery housing 12, flashlight 10 would not be considered a waterproof flashlight.
Although conventional lanterns and flashlights such as that described above, are well-suited for brightly illuminating a relatively small area, they are not well-suited for providing wide area illumination like that produced by a lighting device designed for area illumination, such as a table lamp or gas lamp. Such area lamps, however, are not well-suited for directing a beam of light to illuminate an area a considerable distance away. Because of the need in the market for lighting devices that may serve as both a directional light and an area light, various devices have been constructed that will perform both of these functions. In some of these lighting devices, separate light sources and lenses are provided that may be independently activated. An example of one such light is disclosed in commonly-assigned U.S. patent application Ser. No. 08/690,287. Because two separate switches or a multi-position switch is required to selectively power the separate light sources, and because separate light chambers and lenses must be integrated within the device, these devices tend to be much more complex, bulky, and expensive.
To provide a less complex and less expensive portable lighting device that may function as both a directional light source and an area light, the assignee of the present invention has previously developed a two-in-one portable lighting device that utilizes a single light source, and hence, a single on/off switch. An example of such a lighting device is disclosed in British Patent No. 2,242,732B. These lighting devices include a two-part housing in which a first part of the housing contains the batteries, the switch, and the light to source, and a second part of the housing includes two separate chambers. The first and forwardmost chamber is a directional lighting chamber and the second chamber is defined by a cylindrically-shaped diffusing lens integrated within the cylindrical body of the second part of the housing. The second part of the housing may thus be slid axially along the first housing to reposition the light source within one of the two light chambers. Thus, a user may use such a lighting device as a directional light by sliding the second part of the housing fully within the first part of the housing such that the light source is pushed through a small opening within a reflector of the directional light chamber. Then, to use the device as an area light, the user may fully extend the first part of the housing such that the light source is removed from the directional light chamber into the area light chamber where the light emitted therefrom is transmitted through the cylindrical diffusing lens. Although these portable lighting devices are less expensive and bulky than the portable lighting devices that utilize two separate light sources, they nevertheless remain relatively complex and expensive compared to a conventional flashlight. Furthermore, because the single light source may only be in one chamber at any one time, the portable lighting device may not be simultaneously used as a directional light source and an area lamp. Therefore, there exists a need for a portable lighting device that may operate simultaneously as an area light and a directional light while being easily manufactured at a significantly lower cost.